Butylphthalide has improving effects on impairment of central nervous system function in patients with acute ischemic stroke, can promote the recovery of function in patients, and is mainly converted in vivo into two metabolites, 3-3-(3′-hydroxy)butylphthalide and 3-hydroxy-3-butylphthalide:

Guangdong Zhongke Drug Research & Development Co. Ltd. and Shandong Lvye Natural Drug Research & Development Co. Ltd. synthesized a succinic acid ester, a glycine ester and a phosphoric acid ester of the Metabolite I, and illustrated the use thereof for preventing cerebral ischemic diseases in 2008. Patent application 200410036628.3 discloses a novel use of butylphthalide homologs 3-(3′-hydroxy)butylphthalide and 3-hydroxy-3-butylphthalide. Both of them are proved to have the following effects:
1) significantly improving neurologic symptoms in rats caused by cerebral ischemia due to brain trauma;
2) improving memory disorder in rats caused by cerebral ischemia;
3) relieving cerebral edema in rats caused by cerebral ischemia;
4) reducing stroke in rats caused by cerebral ischemia;
5) improving energy metabolism in rats caused by cerebral ischemia;
6) increasing cerebral blood flow in the ischemic brain region;
7) reducing the area of cerebral infarction in rats with local cerebral ischemia and relieving symptoms of neurological deficit;
8) anti-platelet aggregation and anti-thrombosis;
9) preventing and treating dementia.
Researchers in our company discover that the Metabolite I has two different optical isomers, and have prepared the compound of 3-3-(3′-hydroxy)butylphthalide (Metabolite I) in both S- and R-configurations as is shown in the following figures, by a method of asymmetric synthesis:

Furthermore, it is found by animal tests that the R-configuration cannot affect the cerebral infarct volume in rats with cerebral ischemia and improve the symptoms of cerebral ischemia, while the S-configuration has effects of improving the symptoms of cerebral ischemia and decreasing the cerebral infarct volume in rats with cerebral ischemia. It is also found that the S-configuration of the Metabolite I (the compound of claim 1) has the effect of improving sleep.
The S-configuration of the Metabolite I (the compound of claim 1) is an oily liquid and is insoluble in water. Therefore, in order to prepare it into a dosage form of injectable solution, we have conducted further studies to allow it to become a water-soluble compound by forming an ester with an acid and then forming a salt, to meet the requirement of the formulation.